When Mercury crossed the Sun

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On Wednesday, 7 May, the planet Mercury passed in front of the Sun, giving astronomers - amateurs and professionals - a great opportunity to observe a splendid phenomenon called ""transit"". This phenomenon is very similar to solar eclipses, and Mercury appeared as a tiny black dot slowly crossing the Sun""s disc.

The transits of Mercury occur at intervals between 3 and 13 years, the coming one will be on 8 November 2006. The transit lasted about 5 hours and 20 minutes, and it was globally visible from Asia, Europe and Africa.

Egypt was one of the most favorable places to observe the entire stages of the transit.

Observations from Alexandria

Astronomer Aymen Ibrahim, the Planetarium Astronomy Specialist at the Bibliotheca Alexandrina, observed the transit from the Planetarium using a Sun-spotter, a special optical instrument that projects a magnified image of the Sun onto a screen. Mercury and some other spectacular solar features (sunspots and white-light faculae) were clearly observed in all of the phases of the transit.

Mr. Ibrahim invited the interested public to enjoy watching the heavenly wonder through the Sun-spotter.

Space observations

The event was even observed from space with auxiliary equipment onboard the Euro-American SOHO spacecraft, a solar observatory that orbits the Sun at a distance of 1.6 million km from Earth. The spacecraft tracked the advance of Mercury across the Sun and broadcast it live on its website.

The Planet Mercury

Mercury is the nearest planet to the Sun. With a diameter of about 5000 km, it is less than half the size of Earth, and is somewhat bigger than our Moon. Mercury also is the fastest planet, its year (the time it takes to orbit the Sun once), is only 88 days, but its day is 58 Earth days long!

A Coming Spectacle

Like Mercury, Venus is closer to the Sun than Earth, and gracefully it also passes in front of the Sun. But the transits of Venus are very rare, recurring in periods between 105 and 121 years; and since its orbit is considerably larger than that of Mercury. The last transit of Venus was observed in 1882, and fortunately a transit of Venus is due, on 8 June 2004; again Egypt will be one of the most favorable observing sites for the eagerly anticipated spectacle!

Bibliotheca Alexandrina, the leader of an ancient, glorious era in the history of astronomy invites you to enjoy the coming spectacle - it""s a lifetime experience.


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